Attenuated Parapox viruses can be used to induce Parapox-specific immunity. U.S. Pat. No. 6,162,600. In addition, the highly attenuated strain D1701 (Baypamun HK®) is used as a non-specific immunomodulator (Buttner et al., Immunol. Microbiol. Infect. Dis. 16, 1-10, 1993) to promote immunity to heterologous pathogens. The virus also infects humans and induces nonspecific production of immune modulating cytokines in cultures of human PBMC (Buttner et al., Vet. Immunol. Immunopathol. 46, 237-50, 1995).
Attenuation of Parapoxvirus ovis, however, is time-consuming, taking from 100 to 200 culture passages; according to WO 95/22978, it takes from three to five years to perform each 100 passages, depending on the species of virus used. Attenuation can, therefore, “encompass a period lasting from ten to twenty years.” (See WO 95/22978, page 9).
WO 95/22978 discloses the use of combinations of two or more individual Parapox virus components as “multipotent paramunity inducers” for use as adjuvant therapy for tumors and the prevention of metastases. The components can be individual polypeptides or detached envelopes of poxviruses. WO 95/22978, however, does not disclose any particular viral polypeptides other than the viral fusion protein and adsorption protein. Moreover, WO 95/22978 teaches that the disclosed paramunity inducers have virtually no immunogenic properties. There is a need in the art for simple, effective therapeutic agents that can be used to enhance immune responses and to treat infectious diseases and cell proliferative disorders, including tumors and dysplastic lesions.